Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the first image in a sequence of a display screen or portionthereof with transitional graphical user interface showing my newdesign;

FIG. 2 is the second image thereof;

FIG. 3 is the third image thereof;

FIG. 4 is the fourth image thereof; and,

FIG. 5 is the fifth image thereof.

The dashed broken line perimeter in the drawings illustrates a displayscreen or portion thereof and forms no part of the claimed design. Theremaining dashed broken lines in the drawings illustrate portions of thegraphical user interface that form no part of the claimed design.

The appearance of the transitional image sequentially transitionsbetween the images shown in FIGS. 1-5. This process or period forms nopart of the claimed design.

CLAIM The ornamental design for a display screen or portion thereof withtransitional graphical user interface, as shown and described.